8 A USTRALIAN BOTANY. 



From this small beginning the most complex and wonderful 

 organism, called a ' plant,' is gradually evolved by continual 

 additions to its substance from without, partly from the soil 

 and partly from the air. These substances are changed 

 within the plant into something totally unlike their former 

 appearance. To understand the mode in which this is 

 carried on, we have to learn what is the structure of the 

 organism. 



If a very young part of any plant be viewed under a high- 

 power microscope, minute bladders will be noticed, formed 

 of a very thin skin, filled with a peculiar matter, which 

 in living plants is in continual motion. These minute 

 bladders are called cells, and the enclosed matter proto- 

 plasm, which seems to be the real living matter of the 

 plant, to which all the rest forms either the framework or 

 the food. 1 



The tissues of plants may be simply divided into two 

 kinds — Cellular or Parenchyma, and Woody or Prosen- 

 chyma. 



The following diagrams, A and B, show parenchyma or 

 thin-walled cells — cellulares or plants multiplied by spores — 

 greatly magnified, — A showing spherical loose cells ; B, 

 cells closely packed (polyhedral). 



Plants formed of these alone, like the yeast plant, moulds, 

 mushrooms, mosses, liverworts, etc., are called cellular 

 plants. The spaces between the veins of leaves, the pith 

 of stems, and all the softer portions of the plant, including 



1 Protoplasm, ' first - formative matter,' a general term for the 

 living substance of plants and animals; strictly speaking, \ a clear viscid 

 substance from which tissues are made. It contains nitrogen as an 

 essential ingredient, in addition to the three elements — carbon, oxygen, 

 and hydrogen.'— Sxaith and Field. 



